Typically, in SVC syndrome, the occluded SVC is bypassed predominantly by the azygos, as well as by the internal mammary, lateral thoracic, and vertebral venous systems.1,2 In this patient, the azygos-SVC junction was occluded subtotally as well. Driven by increased venous pressures, unusual collaterals were established between the systemic and pulmonary veins, resulting in a right-to-left shunt. This phenomenon has been described previously in the literature in SVC syndrome, and several anatomic substrates have been identified.2-5 In this patient, the collaterals were most likely the result of reversed flow through anatomic connections between the azygos veins and the pleurohilar pulmonary and bronchial veins. This is a network of veins, rather than a single connection, making this unsuitable for interventions. In this patient, stenting of the azygos-SVC junction restored venous flow from the well-developed azygos vein into the right atrium, diminishing venous pressures, and resulting in collapse of the systemic to pulmonary venous collaterals.